Year	gross (GPI)
1970	0.671019971370697
1971	0.672730028629303
1972	0.677439987659454
1973	0.680140018463135
1974	0.680360019207001
1975	0.688440024852753
1976	0.696129977703094
1977	0.701810002326965
1978	0.7048100233078
1979	0.712719976902008
1980	0.716340005397797
1981	0.723060011863709
1982	0.725470006465912
1983	0.733910024166107
1984	0.731630027294159
1985	0.742990016937256
1986	0.75492000579834
1987	0.762399971485138
1988	0.769209980964661
1989	0.773970007896423
1990	0.779349982738495
1991	0.792349994182587
1992	0.80128002166748
1993	0.812059998512268
1994	0.822369992733002
1995	0.826960027217865
1996	0.832469999790192
1997	0.845499992370605
1998	0.854569971561432
1999	0.865450024604797
2000	0.870519995689392
2001	0.877590000629425
2002	0.885869979858398
2003	0.924480020999908
2004	0.924600005149841
2005	0.929660022258759
2006	0.936119973659515
2007	0.943819999694824
2008	0.956570029258728
2009	0.967840015888214
2010	0.972379982471466
2011	0.976279973983765
2012	0.982079982757568
2013	1.00859999656677
2014	1.01057994365692
2015	1.01259005069733
2016	1.02276003360748
2017	1.02095997333527
2018	0.996980011463165
2019	0.99932998418808
2020	0.994870007038116